Ireland's Central Bank said this morning that a commemorative coin intended to honour James Joyce, which misquotes Ulysses, was "an artistic representation of the author and text and not intended as a literal representation".

The bank announced the launch of 10,000 copies of the collector coin yesterday. Featuring a portrait of the Ulysses author and lines from chapter three of the novel "depicted as a continuous stream of consciousness", it reflects, said governor Patrick Honohan, "Joyce's standing as one of the leading figures in the modernist movement".

Unfortunately, the text quoted on the coin differs by one crucial "that" from the text written by Joyce. The author himself had it that: "Ineluctable modality of the visible: at least that if no more, thought through my eyes. Signatures of all things I am here to read …" The Central Bank included a wayward "that" in its final sentence, with its coin reading: "Signatures of all things that I am here to read."

It acknowledged in a statement today "that the text on the Joyce coin does not correspond to the precise text as it appears in Ulysses", adding that "while the error is regretted, it should be noted that the coin is an artistic representation of the author and text and not intended as a literal representation".

Mark Traynor, manager of the James Joyce Centre, which is dedicated to promoting the author's life and work, called the slip-up "unfortunate", but said there was "certainly a humorous side to it too (no 'flip side of the coin' pun intended)".

"For one thing, Joyce was an author who embraced errors. As Stephen remarks in Ulysses, 'A man of genius makes no mistakes. His errors are volitional and are the portals of discovery'," said Traynor. "So if there is any value in the little mistake by the minters it is that it has bred a new, unexpected narrative. What should have been a fairly mundane launch of a commemorative coin has suddenly reached a much wider audience than expected."

It also just goes to show, Traynor added, "that – even after the cessation of copyright on Joyce's major works – you still can't reproduce a couple of sentences without causing a bit of scandal".

For the Joyce scholar Danis Rose there is at least one marginal saving grace.

"Possessors of the controversial coin can become textual editors in their own right," he said, "by taking a sharp penknife and scraping away the intrusive 'that', thereby producing a definitive edition of the sentence, if defacing legal tender at the same time. This is exactly what Joyce did in his manuscript of Ulysses."

The Central Bank said the coin would still be available to buy, with all new customers informed about the error, and refunds to be offered to those who wished to return it.